diff --git a/calendar/lib.php b/calendar/lib.php
index 43e9de89abc..f378c102b0a 100644
--- a/calendar/lib.php
+++ b/calendar/lib.php
@@ -3016,7 +3016,7 @@ function calendar_get_icalendar($url) {
  * Import events from an iCalendar object into a course calendar.
  *
  * @param iCalendar $ical The iCalendar object.
- * @param int $courseid The course ID for the calendar.
+ * @param int $unused Deprecated
  * @param int $subscriptionid The subscription ID.
  * @return string A log of the import progress, including errors.
  */
@@ -3066,7 +3066,8 @@ function calendar_import_icalendar_events($ical, $unused = null, $subscriptionid
         }
     }
 
-    if (!empty($subscriptionid)) {
+    $existing = $DB->get_field('event_subscriptions', 'lastupdated', ['id' => $subscriptionid]);
+    if (!empty($existing)) {
         $eventsuuids = $DB->get_records_menu('event', ['subscriptionid' => $subscriptionid], '', 'id, uuid');
 
         $icaleventscount = count($icaluuids);
diff --git a/calendar/tests/lib_test.php b/calendar/tests/lib_test.php
index 96af6075ba8..94a3cb4c9f4 100644
--- a/calendar/tests/lib_test.php
+++ b/calendar/tests/lib_test.php
@@ -227,6 +227,24 @@ class core_calendar_lib_testcase extends advanced_testcase {
         calendar_import_icalendar_events($ical, null, $sub->id);
         $count = $DB->count_records('event', array('subscriptionid' => $sub->id));
         $this->assertEquals($count, 1);
+
+        // Test for ICS file with repeated events.
+        $subscription = new stdClass();
+        $subscription->name = 'Repeated events';
+        $subscription->importfrom = CALENDAR_IMPORT_FROM_FILE;
+        $subscription->eventtype = 'site';
+        $id = calendar_add_subscription($subscription);
+        $calendar = file_get_contents($CFG->dirroot . '/lib/tests/fixtures/repeated_events.ics');
+        $ical = new iCalendar();
+        $ical->unserialize($calendar);
+        $this->assertEquals($ical->parser_errors, []);
+
+        $sub = calendar_get_subscription($id);
+        $output = calendar_import_icalendar_events($ical, null, $sub->id);
+        $this->assertStringNotContainsString('Events deleted: 17', $output);
+        $this->assertStringContainsString('Events imported: 1', $output);
+        $this->assertStringContainsString('Events skipped: 0', $output);
+        $this->assertStringContainsString('Events updated: 0', $output);
     }
 
     /**
diff --git a/lib/tests/fixtures/repeated_events.ics b/lib/tests/fixtures/repeated_events.ics
new file mode 100644
index 00000000000..7157007a5a2
--- /dev/null
+++ b/lib/tests/fixtures/repeated_events.ics
@@ -0,0 +1,34 @@
+BEGIN:VCALENDAR
+PRODID:QIS-LSF HIS eG
+VERSION:2.0
+BEGIN:VTIMEZONE
+TZID:Europe/Berlin
+X-LIC-LOCATION:Europe/Berlin
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19700329T020000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19701025T030000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+END:VTIMEZONE
+METHOD:PUBLISH
+BEGIN:VEVENT
+DTSTART;TZID=Europe/Berlin:20191015T160000
+DTEND;TZID=Europe/Berlin:20191015T180000
+RRULE:FREQ=WEEKLY;UNTIL=20200211T235900Z;INTERVAL=1;BYDAY=TU
+LOCATION:O27 - 122
+DTSTAMP:20191002T151421Z
+UID:115808212972
+DESCRIPTION:
+SUMMARY:CS6307.000 - Introduction to Computer Science (for Non-Computer Scientists)
+CATEGORIES:Vorlesung/ Übung
+END:VEVENT
+END:VCALENDAR